Sulfur dioxide has the formula and takes on a trigonal planar electronic geometry, with the two oxygen atoms and the lone pair in the same plane. The molecular geometry will be bent, resulting in a oxygen-sulfur-oxygen bond angle of 120 degrees.

The only answer choice that works is platinum hexafluoride. The platinum molecule is able to bind six fluorine molecules due to the availability of d orbitals in its valence shell. The octahedral shape looks like two pyramids with four sides each that have been stuck together by their bases. We can imagine the platinum at the middle with the six fluorines at each of the vertices of the pyramids. To have the octahedral shape, a molecule must have a central atom and six constituents.

This is the Lewis structure of .

has three bound atoms and one lone pair, so it is sp3 hybridized and trigonal pyramidal. Note that the electronic geometry (geometry including the lone pair) is tetrahedral, but the molecular geometry (excluding the lone pair) is trigonal pyramidal.

Nitrogen is a Group 5 element, so when it is bound to three hydrogen atoms, it will have a lone pair.

has four areas of electron density (three bonds and one lone pair), so its bonds are hybridized.

Because of the lone pair, has a trigonal pyramidal geometry.

Carbon hybrid orbitals are combinations of s and p valence orbitals, and are equal in energy. The hybridization of an atom is dependent on the number of atoms that it is bonded to, as well as the number of lone pairs on the atom in question. A carbonyl carbon is bonded to three other atoms (keep in mind the double bond is not counted twice!) and it has no lone electron pairs. As a result, a carbonyl carbon will exhibit hybridization.

A carbon with four substituents will be hybridized. A carbon with a double bond will be hybridized. A carbon with a triple bond or two double bonds will be hybridized.

Ammonia exhibits a tetrahedral electron pair geometry. It has three bonded pairs (between nitrogen and each hydrogen), and one lone pair (on nitrogen). This combination forms a trigonal pyramidal molecular geometry.

COH2:

:O:

||

H—C—H

This is a trigonal planar molecule, which only has bond angles of 120o

Remember that the d block involves the transition metals. There are 10 transition metal elements per row/period, and those 10 transition elements represent the maximum 10 possible electrons that can be held per d subshell. The d subshell has five orbitals, each with the potential to hold two electrons.

Remember, the energy level is equal to the row number on the periodic table. Looking at row two, the subshells present are s and p. The s subshell can hold a maximum of two electrons since it only has one orbital, while the p subshell can hold a maximum of six electrons since it has three orbitals. Since all of these electrons are in the n=2 energy level, we add them up to get our answer.

There are three bonding electron pairs around the central atom and one non-bonding pair, for a total of 4 electron groups. They arrange spontaneously to be furthest apart according to VSEPR theory, which corresponds to when they form a trigonal pyramidal shape.